Machine for bending tubes, bars, and the like



.1. c. EASTES Nov. 4, 1947.

9 Sheets-$heet 1 Filed July 10, 1944 1 I I a l I I r y I I I I I 1 I I 1I I I I I I I I u I a I u I I I I I I I I I I 1 I r I I I I I l u r I 11R W 0 T 1 N v I 4 w R Q0 F B \m/"M by JAB: 9 m 0 0 W2 H Ev a $1 m Nov.4, 1947. I J. c. EASTES 2,430,217

MACHINE FO R BENDING TUBES, BARS, AND THE LIKE Filed July 10, 1944 9Sheets-Sheet 2 I/ VVelN ToR 2.0412, 8 wal uv Q04,

J. C. EASTES Nov. 4, 1947.

MACHINE FOR' BENDING TUBES, BARS, AND THE LIKE I Filed July 10, 1944 9Sheets-Sheet 3 J. C. EASTES Nov. 4, 1947.

MACHINE FOR BENDING TUBES, BARS, AND THE LIKE Filed July 10, 1944 9Sheets-Sheet 4 INue J. c. EASTES 2,430,217

MACHINE FOR BENDING TUBES, BARS, AND THE LIKE Nov. 4, 1947.

9 Sheets-Sheet 5 Filed July 10, 1944 INi e N701? VLUW J. c. EASTES Nov.4, 1947.

MACHINE FOR BENDING TUBES, BARS, AND THE LIKE 9 Sheets-Sheet 6 FiledJuly 10, 1944 J. QEASTES 2943 033 MACHINE FOR BENDING TUBES,- BARS, ANDTHE LIKE.

Filed July 10, 1944 9 Sheets-Sheet 7 mm- 1 -mnnnnu.

INVEJVT R B 01% M M J. C. EASTE S I MACHINE FOR BENDING TUBES, BARS, ANDTHE LIKE Nov, 4,; 1947.

9 Sheeis-Sheet 8 Fiied July 10, 1944 I IN Vc/VTOR J. C. EASTES Nav 4,1947.

MACHINE FOR BENDING TUBES, BARS, AND THE LIKE Filed Jul 10, 1944 9Sheets-Sheet 9 r wu 0 T N 1% w IR M w m Patented Nov. 4, 1947 STATESPATENT OFFICE MACHINE non BENDING prunes, Baas, AND THE LIKE JohnColbran Eastes, Weybi-i'dg, tennis, igssignorto Vickers-ArmstrongsLimited, Westminster, London, England Application Juiy 10, 1944, SerialNo. 544191 in Great Britain July 10, 1943 12 Claims. 1 The inventionhasforits object toprovide an improved construction of machine for usein bending metal tubes bars arid like objects, including drawn andextruded. metal sections.

A machine in accordance with the invention comprises two dies arrangedin tandem, through which the work-piece is passed in succession, the

first of such dies being Stationary and the second being movable'abouttwo axes inclined to each other and to the longitudinal axis of theunbent work-piece so as't'obe capable of completely universal pivotalmovement about said longitudinal axis in relation'to the stationary die,and means for moving the'pivotal'die in the required direction andfor'impelling or drawin the workpiece through the dies during thebending operation;

Simple bonds, 1. e';,- in which the bent portion of the Work-piece lieswholly in one plane, are produced by-a'movemeht of the pivotal die aboutone axis. Where oompound or helical bends are required a simultaneousmovement of the said be'nds'in d-ifieren-t planes; 'such'for example aswould "be necessary'tofabricate a tubular chairframe from 'a'sin'gl'elength of -stock material, it is convenient to make each successiv bendby moving the pivotal 'die'about the same axis, and to rotate the workpiece between successive bending operations so as'to obtain therequisite angularity of one bend "relative to another. The inventionaccordingly provides means whereby the work-pieoe maybe rotated aboutits longitudinal axis for this ur ose.

The movable die may be operated, and the work-piece may. be rotated;either manually or by power-actuated means such as a hydraulic motor orthe like. i j

The nature of the invention and the manner of its performance arehereinafter more fully explained with reference'to the followingdescription of the eompletelypower-operated tube-bending machine whichis illustrated in the accompanying drawings. In said drawings; Figsl and2 are respectively a longitudinal front. elevation and a plan of thecomplete machine; Figs. 3, 4 9 7 QQ l iYQlu., qnsti ute a Pa t senti elongitudinal elevation of the machine drawnto a arger scale. Fig 6 isjaplan View of that part or the mashing is shown in elevation in Fi 5.Fieflflis aii elvauo or the machine as een noiii'thedieeiid therein.Fig. 8 is a vertical sec ion time tube-feeding carr age whichincorporates self-contained mechanism for rotating th woir ii eceaboutits longitudinal axi Fig. 9 is a longitudinal section or a hydra ireciprocating in'dtortypical of those embodied in the machine. 0 is;'sectionaldetailof the gear transmission between the main 'tub'ef feedmotor um/ease the cam-shaft drive by which th bending dies areactuated.Figs. ll a'rwl 12 re c io a ele t n i e fis se ssf employed to supportthe work-piece respectively as seen in the operative'and open positions,Fig. 13 is a schematic diagr m orit hydraulic ;ap paratus by which theseveral movingmembers of the mac ine are operated, and Fig, 14 isasimilar diagram of the hydraulic apparatus in corporatedinthe tubeifebdingcarriage,

vConsidered in its broadest aspect, the machine illustrated in saiddrawings comprises the essential componentfeatures or rnea'n's for s p;-po'rting the workpiece, the bending jdies L means for theirpperation,means for feeding he Work-piece through the dies, means for jro ting thework piec'e about its longitudinal a 1s, m a r r s iej e speed o e fi ch work-piece durin bending operatibngand irefers to theseseveral'featur's 'seria'tiin.

(a) M 'e'dns for suppbrtiuo the iuoflc-joiec The work-piece, which inthe present instance is exemplified by a length of metal tubing denotedby the reference numeral 2B, is held in axial alignment with the axis'of the stationary die '21 by means of a plurality of spaced steadies'22 (hereinafter more particularly described with reference to'Figs. 11an'd'12) which "are mounted upon the bench'23 of the machine, The rearend of thetube 2B is gripped'by a cdllet 'chllck 24 (Fig. 5), In analternative arrangement not shown in thedrawin'gs said chuck is madetubular so as to be capable of gripping a work-piece at an intermediatepoint in its length.

(12) The bending dies and means for their operation The bendingoperation is performed by feedin the work-piece successively through theaforesaid stationary di 2| and a movable die 25, which latter is mounted'withcapability, of being pivoted independently about a vertical axisand/or a horizontal axis at right angles to the i u i al x srq t en rk-pe e- The statry i i e u l i sisnsd u n hes 9h 23; the movable die 25 ismounted in trunnions 2B which are journalld for movement about 3 theirhorizontal axis between the arms 27 of a carrier 28. The carrier 28 ismounted upon a vertical spindle 29 and supported by an offset bearingbracket 36 fixed to the end of the machine frame.

Mounted beneath the die 25 is a hydraulic reciprocating motor 3| carriedby a bracket 32. Said motor 3! (the internal mechanism and manner ofoperation whereof are hereinafter described with reference to Fig. 9)incorporates a reciprocatory ram 33 at the upper extremity of which isfixed a crosshead 3 1 connected by pivotal links 35 to a pair of pivots36 on the movable die 25, the reciprocatory motion of the ram 33operating to move the die 25 about the horizontal axis of the trunnions2E. The movement of the die 25 about the vertical axis of the spindle 29is efiected by means of a hydraulic reciprocating motor 31 (Fig. 6)through the medium of its ram 38, a lever 39 coupled thereto, and a link48 which connects said lever 39 to a pivot Al on the underside of thecarrier 28. The upper extremity of the ram 33 is socketed to receive thelower end of the spindle 29 so that the latter thus serves to guide saidram 33 in its axial movement. The motor 31 is of similar construction tothe motor 31 and its internal mechanism and manner of operation will beappreciated from the description of Fig. 9, as hereinafter set forth.

The motors 3| and 3'! are of the kind in which a piston-valve arrangedco-axially with the piston rod or ram operates so that a certain degreeof movement of the valve in one direction produces a correspondingdegree of motion of the piston or rain in the same direction. In thecase of the motor 3|, the ram 33 is operated by imparting a suitableaxial movement to the valve 62 which projects from the lower end of themotor, can ing flexible couplings 43, id to the fluid pressure supplyand exhaust and, at its extremity a camfollower 45 (see Figs. 5 and '7).The axial movement of the valve 42 is effected by the cooperation of thecam follower 45 with the edge-cam 46, which is suitably profiled at 45!,A62, and which is mounted on a vertical shaft 41, driven throughspur-gearing Q'H, 472 from the vertical shaft 473 which is in turndriven through bevel-gearing i8, 49 from the horizontal cam-shaft 5S.Similarly, the ram 38 of the motor 3'! is operated by imparting asuitable axial movement to its valve 5| which projects from the end ofthe motor and carries flexible couplings 52,. 53 to the fluid pres--sure supply and exhaust. At the extremity of the valve H is acam-follower 513. The axial movement of the valve 51 is effected by thecooperation of the cam-follower 54 with the edgecam 55, which issuitably profiled at 55| 552, and which is mounted on the said cam-shaft50. Each of the motors 3i and 3'! incorporates a powerful compressedspring (not shown) which acts upon the relative valve (42 or 5!) tomaintain its camfollower (55 or 54) in contact with the profiled face ofthe edge-cam 36 or 55).

() Means for feeding the work-piece through the dies The collet chuck24, by which the work-piece 2B is gripped as aforesaid, is mounted on arotary spindle 60 supported between combined thrustand-journal bearings6| in a saddle 52, the underside of which is formed as a half-nutworking on the lead-screw 63 (Fig. Said screw 63 extends throughout thelength of the bench 23 and is carried at the left-hand end by combinedthrustand-journal bearings 64 (Fig. 3) and intermediate bearings 64 l.The left-hand end of said screw 63 is coupled at 65 to the shaft 66 of arotary fluid motor 67 from which is derived the necessary drive torotate the screw 53 and traverse the saddle 62 along the bench 23, bothwhen feeding the tube 28 through the dies, and when returning the chuck24 to the starting point preparatory to the insertion of a freshwork-piece.

((1) Means for rotating the work-piece about its longitudinal axisPower-operated means are provided for rotating the collet chuck 2d aboutthe longitudinal axis of the tube 29, during the production of a seriesof simple bends lying in different planes, and such means comprise areciprocating fluid-pressure motor ill (of similar type to the motors 3|and 3?) which is disposed in a vertical position in an enclosed carriageconstituted by the casings H, 72, said casing 72 being formed integrallywith the saddle 62. The carriage is additionally supported by a roller73 running on a rail 14 which forms an integral part of the bench 23; aslide 15 on the casing H works alon the surface of the machine bed at 76and a slide 1'! on the casing 12 works along the edge of the bench 23 at18, where it is retained by a rail 19 bolted to the bench. The ram 8i!of the motor 10 is extended in the form of a rack 8|, slidably guided at82, and meshing with an intermediate pinion 83 which in turn meshes witha pinion 84 formed on the stock 2M of the collet chuck 24. Thus, anupward movement of the ram 8i from the datum position depicted in Fig. 8(effected by imparting a corresponding upward movement to the valve 85)produces a partial anticlockwise rotation of the chuck 24 and work-piece20. Similarly, a downward movement of the ram 8! (effected by acorresponding downward movement of the valve 85) produces a partialclockwise rotation of the work-piece 28.

The requisite movements of the valve 85 of said motor 70 are imparted bymeans of cam-like kicker-plates 8B which are bolted to the machine frameat the points in the path of the carriage where they will appropriatelycooperate with either a bowl 8'! rotatably mounted in the foot of thevalve 85, or with a lug 88 which is mounted upon a sleeve 89 surroundingthe ram BI and which is connected to the valve 85, upward movements ofthe valve being brought about by locating the lower kicker-plates 86 inpositions where they will raise the bowl 8'! to the requisite extent,and downward movements of the valve 85 being effected by similarlyadjusting the upper kicker-plates 86 in relation to the lug 88.

The carriage ll, 72 incorporates a self-contained hydraulic system forsupplying fluid pressure to the motor 1B, including a pump 90 driventhrough the gears 95, 96 by a constantly rotating splined shaft 91 atany position of the carriage in its traverse along the machine; saidshaft 91 is driven through the spur gearing l30, l3l from an electricmoto I32.

The angular position of the tube 20 is indicated upon a dial 9! by apointer 92 which is operated through gearing 93, 94 by an arm 98 fixedto the gear 94 and connected at its free end to an upright link 99 whichis pivotally connected to the intermediate pinion 83, the arrangementbeing such that said pointer 92 reproduces the movements of the rack Biand thereby indicates the position of the Work-piece.

ease-sir Whilst it is desirable that the time occupied by the completesequence of operations in the production of a bent work-piece should beminimized, it is on the other hand advantageous to decelerate theworkpiece feed during the actual formation of the bends, in order tofacilitate the control of the machine at such times. The machineillustrated in the accompanying drawings comprises means forautomatically reducing the speed of the work-piece feed during bendformation to' one-half the normal rate,- such means consisting of aregulator valve I governing the fluid pressure supply to the tube-feedmotor 61, said valve ifiil' being controlled by a lever IOI which islinked by a connecting rod I02 witha lever 33 pivoted at lu l; Fixed tosaid lever I03 concentric with its pivot axis is a quadrant 105 whichmeshes with a vertical rack Iilu slidably guided on the machine frameand bee-ring a bowl I'll! which cooperates with the profiled face of anedge-cam I68. A sprin (not shown) serves to maintain said bowl IS? incontact with the cam-face. Said cam I08 is mounted on a shaft I69 whichis driven through the bevel gearing IIU, IiI from the cam-shaft 59, sothat the cam I 58 rotates at the same rate as the came as and 55 whichcontrol the move- I ments' of the dies 2I and 25. The profile of the camI68 is 'deteirnined by the number and relative spacing of the bends inthe work-piece, a depression II2 being provided in the cam-face to bringabeiit the required downward movement of the rack I06 and acons'equentadjustment of the valve Hill as the position of an intended bend isreached, reducing the rate of feed of the work piece 2!! at that pointand for the duration of the bending operation.

The necessity for reducing the speed of the motor '67 arises only duringthe outward journey of the saddle 62, and in order to permit the lat terto be returned as quickly as possible to its starting point, after abent tube has been removed, means are provided in the hydraulic cir-.

cuit relating to the tube feed motor 6'! whereby the valve I85] may bebypassed through a oneway valve which is automatically closed when saidmotor 6'! is running in the forward direction. Further particulars ofsuch by-pass and of said one-way valve are hereinafter given in thedescription of the general hydraulic system of the machine.

(1') Sundry minor features The gearing by which the drive is transmittedfrom the fluid motor 6'! to the cam-shafts B and Hi9 is illustrated inFigs. 3 and 10. A spur wheel iZil on the shaft 66 of the motor 61 mesheswith an idler l2! which transmits the drive to the pinion 522; thelatter is mounted on the shaft I23 of a worm I 24 which drives aworm-wheel I25 through a double worm-reduction gear I26. This is fixedon a shaft 'I2I which is connected by a splined coupling I23, I29 withthe cam-shaft 5%], from which the cam-shaft I09 receives its drivethrough the bevel gearing IIfi, III, as already stated.

The shaft 91, by which the pump 99 on the travelling carriage is driven,receives its rotary motion through the spur gearing I36, I3I from anelectric motor I32.

For the sake of simplicity of illustration the operative faces of theearns :36, 55 and IE8 are shown as though fashioned on a single profiledannulus in respect of each cam, and it would of course be possible toprovide a separate annulus for each cam to suit each given sequence ofbending operations. As will however be understood, it

=' is more practical to make the cam carriers of plain drum shape and toprovide means for bolting thereto independent cam-plates of suitableprofile and length according to the relative timing and respectiveduration of the bending operations, such cam-plates being capable ofbeing rapidly and easily adjusted in preparation for a differentsequence of operations.

The steadies 22, by which the work-piece 28 is supported in the machinewhilst being fed through the dies, are illustrated on a larger scale inFigs. 11 and 12 of the drawings. Each steady comprises a bracket 22I inwhich a slide 222 is adapted to move between the respective positionsshown in Figs. 11 and 12 along a line at right angles to thelongitudinal axis of the workpiece 2%. The slide 222 carries at itsinner extremity an arcuate pad 223 which, when the slide is in theposition shown in Fig. 11, constitutes a support for the work-piece.Pivoted at 22s to said slide 222 is a lever 225 attached by a pin andslot connection 225, 22? to a hand-lever 22 8 connected by a link 22% toa fixed pivot 2323 on the bracket 22E. A tension spring 23! c nnects thepin 22% with a fixed anchorage 232 and is arranged to exert arectilinear pull in a rearward direction upon the pin 226 in such manneras to tend to raise the lever 225 to the position shown in Fig. 12. Thelever 22% has at its free extremity a semi-cylindrical cap 2-33, which,when the lever 225 is in the position shown in Fig. 11, serves toembrace the work-piece where it is supported by the pad 223 of the slide22L In this p6sitioh,.'the pin 22%, the hand-lever 223, the link 229 andthe pivot 230 all lie in the same plane, forming collectively a bracedtoggle, and

the spring 23! is accordingly incapable of retracting the slide 222.When, however, the handlever 228 is tipped upwardly about the pivot-pin225, the toggle is broken and the slide 222 is automatically withdrawnfrom the work-piece; the lever 225 and can 233 are simultaneously raisedby said spring EM, and the device assumes the open position shown inFig. In order that the steadies may be moved to the open positionautomatically as the tube 20 is fed through the dies, to permit thetube-iced carriage to pass the steadies as it approaches each in turn,an abutment 234 (Fig. 6) mounted on the casing if; of

said carriage is adapted to impinge against and moment. When a bendingoperation is concluded, there exists between the movable die and thefixed die a short length of bent work-piece, which must pass through theaperture of the movable die without bending still further. To enable themovable die to accommodate itself to the forwardly moving work-piecewithout deforming the latter, it is consequently necessary to provide aspherical housing in which the operative portion of the'mo-vable die canpivot universally at this time; in the machine shown in the accompanyingdrawings such housing is indicated at 25, but the operative portion ofthe die is not shown.

(g) Construction of reciprocatory hydraulic motor The motors 31, 3'. and70 are all of similar type and, as aforesaid, are characterised by anarrangement whereby the movement of a piston valve produces acorresponding extent of movement of the ram in the same direction. Atypical motor of this kind is illustrated in Fig. 9 of the drawings,from which it will be seen that the motor comprises a cylinder 306 inwhich works a piston 30! fixed to a tubular ram or pistonrod 302 whichis guided at the ends of the cylinder by suitable stufling-glands 303.On opposite sides of the piston the rod 302 is furnished with pairs ofdiametrically opposed ports 304, 305 and 306, 30?, and slidable withinthe bore of said rod 302 is a piston-valve 308 bored longitudinally toprovide a fluid pressure inlet chamber 350 and a fluid pressure exhaustchamber 3H3, which chambers are respectively connected with flexi blesuppy and exhaust pipes 3i 1, 3l2. The inlet chamber 309 of the valve isprovided with two inlet ports 313, SM, spaced at such distance apartthat a longitudinal movement of the valve 308 is required to registerone of its said inlet ports with one of the inlet ports 30 i, 300 of thepiston-rod 302 to permit working liquid under pressure to enter thecylinder. The exhaust chamber Bill of the valve is provided with anexhaust port 305 or 301 of the piston-rod when th valve 308 is moved toadmit pressure to the opposite side of the piston 30 I.

To produce a movement of the ram or pistonrod 302 towards the left asviewed in Fig. 9 (corresponding for example to the upward movement ofthe ram 33 of the motor 3|) the valve 308 is moved in the samedirection, admitting liquid under pressure from the inlet chamber 309through the ports M3 and 314 to the right-hand end of the cylinder 300,and connecting the lefthand end of the cylinder to exhaust through theports 301 and 3l5. The piston 30! and ram 302 continue to move until theport 3!?! has been masked by the piston-rod 382 and the port 3l5 by thepiston itself, when movement ceases; thus the length of stroke of theram 302 corresponds exactly with the extent of movement of the valve308, The reverse operation, in which the liquid under pressure entersthe left-hand end of the cylinder through the ports 3M and 306, and theright-hand end of the cylinder is connected to exhaust through the ports305 and N5, is performed in like manner on the movement of the valve 308towards the right.

(h) Hydraulic operating system The hydraulic system employed for theoperation of the machine hereindescribed incorporates three independentsub-systems the respective functions whereof are (I) The provision ofpower for the tube-feed motor 61,

(II) The provision of power for the die-operating motors 3i and 31, and

(III) The provision of power for operating the tube-rotating motor onthe travelling carriage.

The first and second of these sub-systems are diagrammatically depictedin Fig. 13 ofthe drawings, and the third sub-system is similarly shownin Fig. 14. In Fig. 13 high-pressure pipe-lines are drawn in full, thesingle lines denoting medium pressure circuits.

I. Referring to Fig. 13, it will be seen that hydraulic fluid is drawnfrom a reservoir 400 by a pump dill, driven by a constantly runningelectric motor Q02 (see Fig. 4), and delivered by the pipe 403 through arelief-valve 504 to a four-way valve G05, which acts as an on-off valve,either delivering fluid to the circuit of the tube-feed motor 81 throughthe pipe 405 or returning the fluid to the reservoir 400 by way of aspringloaded check-valve 001 and the pipes 408, 409. Said valve 405 isof the well-known moving-spool type capable of being operated by a lowpressure pilot circuit; in this case the pilot circuit lines indicatedat M0, Ml are controlled by a master pilot-valve M2, pressure for thepilot circut being obtained through the pipe H3 from the pressure sideof the relief-valve 404.

When the operating lever of the pilot-valve 412 is moved to the positionA (indicated in dotted lines), the line M0 is connected to the exhaustline and connection is made through the valve between the lines #113 andM I, thus applying pressure to the right-hand end of the valve 405 andmoving the spool of this valve to the left, the effect of which is toconnect the pipe 403 to the check-valve 401 and the pipe 406 to a pipe4M which leads into the return pipe 109, so that fluid flows throughsaid check-valve 401 and back by the pipe 509 to the reservoir, This isthe off position of the valve 405 and no power is supplied tothetube-feed motor 57. The purpose of the check-valve which is heavilyspring-loaded, is to maintain a pressure of approximately pounds persquare inch in the system, which pressure would suiiice to operate thepilot-valve H2.

If the pilot-valve M2 is moved to the position indicated at B, the line4 is connected to the exhaust G20 and communication is establishedbetween the lines M3 and 4H], so that the valve 405 is reversed, movingto its on position, in which fluid flows by the pipes 503 and 406 to areversing-valve M5. The valve M5 is likewise of the moving-spool type,and is controlled through a pilot circuit 4H5, ll'i by means of apilot-valve 448 (front bank) deriving pressure from the line M3 by abranch M0. With the lever of the pilotvalve 558 in the positionindicated at C, the line M6 is connected to the exhaust line 420 andcommunication is established between the pressure line M9, M3 and theline M7; the effect of this is to move the spool of the valve 415 toconnect the pressure line 508 to the pipe 42l of the tubefeed motorcircuit, the other line 622 of this circuit being connected to thereturn pipe 409, so that fluid flows by the pipe 42! through thespeedcontrol valve I00 to the motor 67, returning thence through thepipes 422 and 009. The motor 0! is now running in an anticlockwisedirection, driving the screw 63 to feed the saddle 62 and tube 20forward towards the bending dies.

On reaching the end of the travel of the carriage, the dog an on thelever of the pilot-valve H8 is tripped by an abutment 424 on the casing'12 and said lever is moved to the upright or neutral position. Thespool of the valve M5 is centralised by its control spring and the fluidsupply to the tube-feed motor 0'! through the pipe MI is shut off. Themotor 61 is thus stopped to enable the bent tube to be removed from thechuck 2d.

The lever of the pilot-valve 418 is next moved to the position D, sothat the line 4| 1 is connected to the exhaust line 420 andcommunication is established between the lines M9 and M6, reversing thevalve i I 5 anddelivering fluid to the tube-feed motor 61 in theopposite direction, 1. e., by way of the pipe 422, returning to thereservoir through the one-way valve 62-5 (by-passing the speed controlvalve lee) and the pipes HI and 469; thus, the rotation of the motor 61is reversed and the saddle 62 returns to its starting point at fullspeed, the effect of by-passing the valve Iilil being to prevent the cam188 from afiecting the speed of the carriage on its return journeyduring which no bending operations are taking place.

When the tube-feed carriage reaches the full return position a camabutment Q26 carried on the casing 72 impinges against the operatinmember of a valve 421, the efiect of which is to arrest the travel ofthe carriage in the following manner:

The relief-valve 404 being of the balanced piston type, its piston willrise when pressure on its upper side is released, permitting fluid inthe line 493 to return freely to the reservoir 408. A pipe 3-28 connectsthe unloading chambers of the valve ied to one side of the valve 421,and when the valve the is in the normal position said line 428 is closedand pressure in the relief-valve 564 is maintained. When, however, thevalve 42'! is actuated by the cam abutment 425 on the return of thecarriage, the line 528 is connected through the Valve t2! to the line429 and fluid in the line 428 is thus allowed to escape through thebranch 43% into the line 421 by which it may return to the reservoir,thus unloading the relief-valve MM and removing pressure from thecircuit feeding fluid to the motor 61.

It is convenient to provide a similar pressurerelease valve, i. e., thevalve 43!, connected in parallel with the valve d2! but arranged to beoperated by a dog 432 on the speed control cam H38. By adjusting theposition of said dog 532 in the T-groove provided in the periphery ofthe cam its (see Fig. 3), the return stroke of the saddle 62 may bearrested at any desired point, so that where a tube 29 to be bent isshorter than the maximum length of work-piece permitted by thedimensions of the machine, the starting point for the sequence ofoperations may be adjusted accordingly.

To start a new cycle of operations with either of the valves it? or seaopen, it is suflicient to move the lever of the pilot-valve M8 to theposition C. This action connects the pipe 62! to pressure, so that therelief-valve 454 is restored to its normal balanced condition byre-pressurising the lines sac, 329 and 428, and as soon as the carriagehas moved forward from th startingpoint, the valve A2? (or A3!) isreleased and closed.

The pilot-valve M2 serves as a master valve for the control of the wholemachine. The tube-feed motor '33 may be stopped at any position bymoving the lever of the valve M2 to the position A.

II. Working liquid is supplied to the sub-system for operating the diemotorssi and 31 from a reservoir see by a pump 45! driven by amotor 352.The pump 65! incorporates a relief-valve 453 by which the pressure inthis system may be set at a predetermined maximum, say 500 pounds persquare inch. The pump d5! delivers fluid through the pipe 45 to the rearbank of the pilotvalve 453 the connections made by which are such that,when the tube-feed motor 5! is running anticlockwise to feed thework-piece towards the dies, fluid is delivered under pressure throughthepipes 455,456 .and 45! tothedieoperatingmotors Stand ,31 past thecheck-valve $58. On the return of the carriage to the starting point,when the valve 418 isain position D, the

fluid delivered by the pump 45! returns freely to the reservoir 350byway of the pipe 4'59. The exhaust connections ,irom the motors 3i and31 lead into the return pipe 169. The check-valve 353 servesto maintainthe cylinders of the motors 3i and 37, and the pipes 456 and 351 full ofworking liquid at all times, although the operating pressure of suchmotorsis only, obtained when thepilot-valve M8 is in position C.

111. The sub-system relating to the tube-rotatin motor l9 isdepicted inFig. 14, from which it will lee-seen that the low-pressure pump drawsworking \iluid from the reservoir 48! and delivers it through the pipeltz past the reliefvalve @233 to the pressure inlet of the motor m, theexhaust connection whereof is'indicated at so l. The relief-valved-litserves to permit pressure fluid to return to the reservoir .48!when the motor To is at rest.

What I claim asmy invention and'desire to secure by Letters'Patent is:

1. A machine for bending metal tubes, bars and like objects, comprisingtwo diesarrangedgin tandem, through which the work-piece is passed insuccession, the first of such dies being stationary and the secondmovable about two axesinclined to each other and to the'longitudinalaxis of the unbent work-piece so as to be capable of completelyuniversalpivotal movement about said longitudinal axis in relation tothe stationary die, means for moving the pivotal die in the requireddirection, and means for moving the work-piece through the diesrduringthe bending operation.

2. A machine for bending metal'tubes, bars and like objects, comprisingtwo dies arranged in tandem, through which the work-piece is passed insuccession, the first of such'dies being stationary and the secondmovable about two axes inclined .to each other and to the longitudinalaxis of the unbent work-piece so as to be capable of complete- 1yuniversal pivotal movement about said longitudinal aXis in relation tothe stationary die, means for moving the pivotal die in the requireddirection, means formoving the work-piece through the dies during thebending operation and means for rotating the work-piece about itslongitudinal axis during its passage through the dies.

3. A machine as claimed in claim 1, wherein the movable die is mountedfor pivotal movement about a vertical axisand a horizontal axisperpendicular to the longitudinal axis of the unbent work-piece, eitherselectively or simultaneously, comprising two reciprocatory motors themoving members whereof are respectively linked to two pivots associatedwith the movable die, one such pivot being parallel to but off-set fromthe vertical pivotal axis of the die and the other pivot being parallelto but off-set from the horizontal pivotal axis of the die.

4. A machine as claimed in claim 1 comprising means for reducing thespeed at which the work-piece is advanced through the bending dies, suchspeed-reducing means operating automatically as each bending operationcommences and for the duration thereof.

5. A machine as claimed in claim 2, comprising a carriage associatedwith the gripping means and arranged to traverse the machine as thework-piece is advanced to the bending dies, a reciprocatory motor onsaid carriage and gearing between the movable member of said motor andsaid gripping means in such fashion that the operation of said motorproduces a partial rotation of the work-piece.

6. A machine for bending metal tubes, bars and like objects, comprisingtwo dies arranged in tandem, through which the work-piece is passed insuccession, the first of such dies being stationary and the secondmovable about two axes inclined to each other and to the longitudinalaxis of the unbent work-piece so as to be capable of compl telyuniversal pivotal movement about such longitudinal axis in relation tothe stationary die, means for moving the pivotal die in the requireddirection, means for supporting the unbent portion of the work-piece atspaced points in its length preparatory to and during its passagethrough the bending dies, means for gripping the rear end of thework-piece, a push-bench for said gripping means, means for advancingsaid gripping means along the push-bench to impel the work-piece throughthe dies, and means for reducing the speed at which the work-piece isadvanced through the bending dies, such speed-reducing means operatingautomatically as each bending operation commences and for the durationthereof.

7. A machine as claimed in claim 6, comprising a saddle associated withthe work-piece gripping means, a lead-screw cooperating with a nut onsaid saddle to traverse the latter along the push-bench in eitherdirection according to the rotation of said screw, and a rotary motorfor driving said screw.

8. A machine as claimed in claim 6, comprising a saddle associated withthe work-piece gripping means, a lead-screw cooperating with a nut onsaid saddle to traverse the latter along the push-bench in eitherdirection according to the rotation of said screw, a rotary motor fordriving said screw, a cam driven by the rotary motor, a regulator forvarying the speed of said motor,

and a cam-follower operatively connected on said regulator and adaptedto cooperate with the face of said cam, said cam being shaped to efiectthe necessary movements of said regulator through the medium of thecam-follower to vary the motor speed as required.

9. A machine for bending metal tubes, bars and like objects, comprisingtwo dies arranged in tandem, through which the work-piece is passed insuccession, the first of such dies being stationary and the secondmovable about two axes inclined to each otherv and to the longitudinalaxis of the unbent work-piece so as to be capable of completelyuniversal pivotal movement about said longitudinal axis in relation tothe stationary die, means for moving the pivotal die in the requireddirection, means for moving the work-piece through the dies during thebending operation, a carriage associated with the gripping means andarranged to traverse the machine as the work-piece is advanced to thebending dies, a reciprocatory motor on said carriage, gearing betweenthe movable member of said motor and the gripping means so arranged thatthe operation of said motor produces a partial rotation ofthe-workpiece, and control means for said reciprocatory motor, saidcontrol means comprising cam-like kicker-plates located in the path ofthe carriage and means adapted to engage said kickerplates for actuatingsaid motor in the appropriate direction at the requisite stages in themovement of the work-piece through the dies.

10. A machine for bending metal tubes, bars and like objects, comprisingtwo dies arranged in tandem, through which the work-piece is passed insuccession, the first of such dies being stationary and the secondmovable about two axes inclined to each other and to the longitudinalaxis of the unbent work-piece so as to be capable of completelyuniversal pivotal movement about said longitudinal axis in relation tothe stationary die, means for moving the pivotal die in the requireddirection, means for moving the workpiece through the dies during thebending operation, two reciprocatory motors, the moving members whereofare respectively linked to two pivots associated with the movable die,one of such pivots being parallel to but offset from the verticalpivotal axis of the die, and the other pivot being parallel to butoffset from the horizontal pivotal axis of the die, each of saidreciprocatory motors havin a cam-follower associated therewith, and acam adapted to engage each of said cam-followers, said cams being shapedto effect the movements of the cam-followers which are requisite toactuate the respective motors so as to pivot the vmovable die throughthe desired angle.

11. A machine as claimed in claim 10, said reciprocatory motors eachcomprising a cylinder, a piston, and a piston-valve so arranged thatmovement of the piston-valve causes corresponding movement of the pistonin the same direction.

12. A machine for bending metal tubes, bars and like objects, comprisingtwo dies arranged in tandem, through which the Work-piece is passed insuccession, the first of such dies being stationary and the secondmovable about two axes inclined to each other and to the longitudinalaxis of the unbent work-piece so as to be capable of completelyuniversal pivotal movement about said longitudinal axis in relation tothe stationary die, means for moving the pivotal die in the requireddirection, means for moving the work-piece through the dies during thebending operation, means for reducing the speed at which the work-pieceis advanced through the bending dies, such speed-reducing meansoperating automatically as each bending operation commences and for theduration thereof, and said speed-reducing means being automaticallyrendered inoperative when said mechanism is returned in reverse to itsstarting position.

JOHN COLBRAN EASTES.

REFERENCES CITED 6O The following references are of record in the fileof this patent:

UNITED STATES PATENTS Number Name Date 5 717, 78 Earle Dec. 30, 19021,936,765 Lawson Nov. 28, 1938 2,306,224 Parker et a1 Dec. 22, 19422,341,178 Duer Feb. 8, 1944 2,357,312 Duer Sept. 12, 1944

